Idleness in battle (8)

I believe the answer is:

inaction

'idleness' is the definition.
(thesaurus)

'in battle' is the wordplay.
'battle' becomes 'action' (military action).
'in'+'action'='INACTION'

(Other definitions for inaction that I've seen before include "Failure to do anything" , "Inertia" , "Failure to exert oneself" , "Sloth" , "Idleness of nicotian sort" .)

I've seen this clue in The Irish News and The Globe and Mail.

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